1. Field of the Invention
The present invention relates to a photographic light-sensitive material capable of forming images having improved granularity and sharpness, and more particularly, it relates to a color photographic light-sensitive material capable of forming color images having improved granularity, sharpness and color-reproducing properties, which contains a color-forming coupler releasing a development inhibitor when reacted with an oxidation product of color developing agent and of which the storability is improved.
2. Description of the Prior Art
Recently, increasingly the tendency has been to require color photographic light-sensitive materials in which more information can be recorded per unit area.
Since the availability of silver as a raw material has been gradually reduced, it is desired to decrease the amount of silver halide to be incorporated in photographic light-sensitive materials and to form images on smaller areas of photographic light-sensitive materials. However, in order to produce photographic light-sensitive materials with these characteristics, the granularity, sharpness and color separation of images formed by the materials must be improved further.
Further, it is desired for the storability of color photographic light-sensitive materials to be improved because they are employed for various purposes and stored for long periods of time under various conditions.
Hitherto, the following techniques have been proposed to meet the above requirements. One technique is a method employing a so-called development-inhibitor releasing coupler (DIR coupler). A DIR coupler is a coupler capable of forming a dye and simultaneously releasing a development inhibitor by an oxidation coupling reaction with a color developing agent as disclosed in C. R. Barr, J. R. Thirtle and P. W. Vittum, Photographic Science and Engineering, Vol. 13, pages 74 to 80, and pages 214 to 217 (1969), and U.S. Pat. No. 3,227,554.
Typical examples of DIR couplers are monothio-type couplers having a coupling-off group in which a sulfur atom, a selenium atom or a tellurium atom is bonded to the carbon atom at the coupling position of the couplers (for example, as disclosed in U.S. Pat. Nos. 3,227,554 and 3,733,201, German Patent Application (OLS) No. 2,247,496, etc.), and imino-type couplers having a coupling-off group in which a nitrogen atom is bonded to the carbon atom at the coupling position of the couplers (e.g., as disclosed in U.S. Pat. Ser. No. 454,525, filed Mar. 25, 1974 and now U.S. Pat. No. 3,933,500) (interlayer color correction (I.C.C.) couplers)). A monothio-type coupler is generally advantageous for improving granularity and edge effects, but provides a development inhibiting effect in the light-sensitive emulsion layer containing the coupler in preference to an inter-image effect. In other words, the image sharpness can be improved using the coupler due to the granularity and edge effects generated by the coupler but this coupler reduces the gradation (gamma) of the light-sensitive layer in which the coupler is contained and reduces the maximum color density (D.sub.max). This coupler also deteriorates the storability of light-sensitive materials. An imino-type coupler provides a development inhibiting effect between light-sensitive emulsion layers (e.g., an inter-image effect or a color correction effect) which is more marked than that observed in the light-sensitive emulsion layer in which the coupler is contained. This coupler also possesses the comparatively excellent properties of a two equivalent coupler and it hardly reduces gradation and D.sub.max. However, an improvement of image granularity can not be expected in general on using an imino-type coupler.
Another technique is a method employing a colored coupler having an auto-masking function as disclosed in U.S. Pat. Nos. 2,449,966, 2,455,170, 2,600,788, 2,428,054, 3,148,062 and 2,983,608, and British Pat. No. 1,044,778. However, since the unexposed portions of photographic materials are always colored by a colored coupler, this coupler can not be employed in positive color photographic materials. Further, fog tends to occur due to the product which is produced where an arylazo group of the colored coupler is released and the granularity is deteriorated by fog.
Other techniques are known, for example, a method employing an inter-image effect accelerating agent as disclosed in U.S. Defensive Publication Nos. T909,022 and T909,023, a method employing an intermediate layer containing a direct positive emulsion or an internally fogged emulsion or a method employing a Luckey effect, but the results thereof are not necessarily sufficient. Further, a method is known in which the iodine content in the light-sensitive silver halide emulsions, the habit of the silver halide crystals, the developing rate, the components of the developing solutions or the developing conditions are controlled as disclosed in Japanese Patent Application No. 33,238/73, but the results obtained are not sufficient.